http://dspace.nbuv.gov.ua:80/handle/123456789/150363 2026-04-18T13:16:27Z 2026-04-18T13:16:27Z Khripchenko, N. http://dspace.nbuv.gov.ua:80/handle/123456789/154604 2019-06-15T22:31:50Z 2010-01-01T00:00:00Z

Automorphisms of finitary incidence rings Khripchenko, N.

2010-01-01T00:00:00Z Kashu, A.I. http://dspace.nbuv.gov.ua:80/handle/123456789/154603 2019-06-15T22:32:30Z 2010-01-01T00:00:00Z

Preradicals and characteristic submodules: connections and operations Kashu, A.I. For an arbitrary module M∈R-Mod the relation between the lattice Lch(RM) of characteristic (fully invariant) submodules of M and big lattice R-pr of preradicals of R-Mod is studied. Some isomorphic images of Lch(RM) in R-pr are constructed. Using the product and coproduct in R-pr four operations in the lattice Lch(RM) are defined. Some properties of these operations are shown and their relations with the lattice operations in Lch(RM) are investigated. As application the case RM=RR is mentioned, when Lch(RR) is the lattice of two-sided ideals of ring R.

2010-01-01T00:00:00Z Umar, A. http://dspace.nbuv.gov.ua:80/handle/123456789/154602 2019-06-15T22:32:00Z 2010-01-01T00:00:00Z

Some combinatorial problems in the theory of symmetric inverse semigroups Umar, A. Let Xn={1,2,⋯,n} and let α:Domα⊆Xn→Imα⊆Xn be a (partial) transformation on Xn. On a partial one-one mapping of Xn the following parameters are defined: the height of α is h(α)=|Imα|, the right [left] waist of α is w+(α)=max(Imα)[w−(α)=min(Imα)], and fix of α is denoted by f(α), and defined by f(α)=|{x∈Xn:xα=x}|. The cardinalities of some equivalences defined by equalities of these parameters on In, the semigroup of partial one-one mappings of Xn, and some of its notable subsemigroups that have been computed are gathered together and the open problems highlighted.

2010-01-01T00:00:00Z Cangelmi, L. Muktibodh, A.S. http://dspace.nbuv.gov.ua:80/handle/123456789/154601 2019-06-15T22:32:29Z 2010-01-01T00:00:00Z

Camina groups with few conjugacy classes Cangelmi, L.; Muktibodh, A.S. Let G be a finite group having a proper normal subgroup K such that the conjugacy classes outside K coincide with the cosets of K. The subgroup K turns out to be the derived subgroup of G, so the group G is either abelian or Camina. Hence, we propose to classify Camina groups according to the number of conjugacy classes contained in the derived subgroup. We give the complete characterization of Camina groups when the derived subgroup is made up of two or three conjugacy classes, showing that such groups are all Frobenius or extra-special.

2010-01-01T00:00:00Z